| With the development of science and technology constantly，human influence onatmospheric environment is more and more serious and form the acid precipitation,what the people common referred to as "acid rain" is the atmospheric precipitationPH below5.6suchas"freezingrain"Snow"hail"and"dew". Acid rain has broughtserious impact and destruction to the ecological environment of the earth and humansocial economy, precipitation chemistry has attracted highly attention. In order toinvestigate the characteristics of precipitation contamination of the Nanchang CityRegio. This sbuject has research he chemical composition of precipitation inNanchang from May15,2013to January11,2013. Use the concept of ion balanceanalysis，relative acidity and The effects of meteorological factors and the deductionof deduction of sea salt analysis of Nanchang City in precipitation chemicalcomposition distribution and the influence by the human activities to theprecipitation。Some results were obtained.Mainly include:(1)K+, Na+, Ca2+, Mg2+, NH4+, SO42-, NO3-, F-, Cl-are the main soluble ion inthe precipitation of new city Nanchang City. SO42-and NO3-are the main anions inprecipitation and the78%of the total number of anions, Ca2+and NH4+are the maincation in precipitation and the86%of the total number of cation.(2)The total ion concentration in the sapmling period of the range of new cityNanchang City Nanchang City is183.67-380.19μeq/l and the weighted averageconcentration is318.2μeq/l. Precipitation is moderate pollution,77%in the rainsample total.(3)Owing to the rainfall is large in the summer in new city of Nanchang, thecleaning of particulate matter in the atmosphere by precipitation is strong，and there islow rainfall in the winter, the cleaning of particulate matter in the atmosphere byprecipitation is weak, SO42-usually in large particle matter in the atmosphere, soSO42–has no obvious change with the seasons, The sampling point of NO3–is underthe influence of the Fengsheng highway. The ratio of the SO42-/NO3-in the rain in Nanchang is between0.5to3, the Precipitation pollution type is sulfuric acid-nitratecompound in Nanchang. By means of comparing to SO42-/NO3–in the rain inNanchang in the past. It is becoming more and more serious affected by NO3–in Nanchang.(4) Factors to the acid in the rain were SO42-and NO3-, The main neutralizationfactor were Ca2+and NH4+. The contribution of Ca2+to neutralize the acidity is bigthan NH4+.(5) Na+, Cl-, Ca2+and Mg2+in the rain in new city of Nanchang have the similarsources. Almost all of the K+and Ca2+comes from the contribution of land. Amongthem,. K+and Ca2+derived from the weathering rock or soil. Mg2+affected by the seaand land at the same time. All of SO42-、NH4+and NO3-is from the land, SO42-mainlycomes from human activities that burning of fossil fuels as the main, NH4+mainlycomes from human activities that produce ammonia.Nanchang new precipitationpollution is mainly caused by human activities.(6)The acid rain frequency in Nanchang is95%, the rainfall are all excaptAugust and Septenber, the average precipitation pH of Nanchang is4.45, and it showscharacteristic that pH in the winter is lower than other seasons. The conductivitymean is34.28μs/cm, it represents that precipitation pollution of new city Nanchangcity is very serious.(7)Analyzing the pH and conductivity we can find that the higher the pH, thesmaller the conductivity, the pH and conductivity shows a significant negativecorrelation, reflect the acidity that the greater the conductivity, the greater the rainfallpollution is more serious.(8)Rainfall and relative humidity has a certain influence on the pH value ofprecipitation. Rainfall was positively correlated with the pH values, relative humidityand precipitation pH value showed a negative correlation. |
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